This invention relates to gas insulated circuit breakers and, more particularly, to single enclosure multi-interrupter arrangements with associated operating mechanism all enclosed within the single enclosure.
A general object of the present invention is to provide an improved circuit breaker in which all of the circuit interrupters are contained within a single enclosure and the interrupters are supported within the enclosure by their own high pressure gas container.
A more specific object of the present invention is to provide an improved gas insulated circuit breaker particularly well suited for a multi-interrupter arrangement in which each interrupter has its individual high pressure gas container which also supports the interrupter in electrically isolated relationship within the enclosure.
Yet another object of the present invention is to provide an improved multi-interrupter gas insulated circuit breaker having improved means of inserting and withdrawing the interrupters from the enclosure.
In U.S. Pat. Nos. 3,852,548 and 3,852,549, assigned to the assignee of the instant application, there is disclosed a multi-interrupter single tank breaker in which the high pressure gas container is located externally of the enclosure. In the aforesaid patents, the interrupters are supported by a top sleeve and stabilized by an insulator sleeve which is in communication with the external high pressure gas container. In the construction disclosed in these patents, the interrupters receive the high pressure gas from a single container with the gas being diverted in opposite directions to the interrupters. Operation of the contacts and blast valves is effected by vertically arranged operating mechanism which is contained within a housing on the enclosure.
In U.S. Pat. No. 3,057,983, a gas insulated circuit breaker is disclosed in which a plurality of serially arranged interrupters are utilized. In the arrangement disclosed therein, the high pressure reservoir and a blast valve mechanism are disposed adjacent one end of the arc extinguishing assembly which bridges the space between spaced terminal bushings. Support of the interrupter assembly is obtained from the terminal bushings. The general operation of the above-identified interrupter is such that during the opening operation a single blast valve opens to allow the gas from the high pressure chamber to blast through a plurality of blast tubes and into the interrupting units. In other words, the interrupter furthest from the high pressure chamber is expected to receive its share of the gas blast as soon as the interrupter which is closest to the high pressure source receives its share.
In U.S. Pat. Nos. 3,007,021 and 3,852,549, structures for servicing the interrupters are disclosed. In the former patent, a monorail structure is utilized which, when used, is bolted to the lower end of the terminal bushings. This arrangement puts stress on the terminal bushings subjecting them to lateral forces which may inadvertantly damage them. Such damage that may occur could go unnoticed when removing or reinserting the interrupters within the enclosure. The damage may cause premature failure of the unit. As shown in the patent, the external end of the monorail requires a relatively massive A-frame to support the end of the monorail. In U.S. Pat. No. 3,852,549 assigned to the assignee of the present invention, there is disclosed an interrupter handling arrangement which includes a pair of spaced apart parallel rails on which the interrupters are guided into and out of the enclosure. This arrangement requires additional structure to be formed on the interrupter casting, which structure extends outwardly of the interrupter. This arrangement requires external supporting structure which is bolted to the access door flange. Both arrangements, while providing means for handling the relatively heavy interrupters, are massive and awkward to use especially in confined locations.